Tinting water-borne and solvent-borne paints and stains with powdered colorants

ABSTRACT

A point-of-sale custom color system for tinting base paints and stains includes an array of powdered colorants, including at least white, green, blue and red colorants, which can be used to tint water-borne paints and stains. When tinting solvent-borne base paints or stains, a synergist containing one or more cosolvents, dispersing agents or surfactants is added to or is a part of the solvent-borne base paint or stains, and enables effective tinting using the powdered colorants.

FIELD

This invention relates to point-of-sale customized-color architectural paint and stain tinting systems, such as those used in retail paint stores to make custom-tinted house paints or stains.

BACKGROUND

Architectural paint and stain manufacturers typically distribute premixed paints and stains in a small number of popular colors. To accommodate consumer desires and enable matching of existing painted or stained surfaces, manufacturers typically also distribute a set of tintable base paints or stains and several liquid colorants. These are combined at point-of-sale outlets using volumetric colorant dispensing equipment and shaker mixing equipment to make small batch lots of custom-tinted paint or stain in a much larger array of colors than the limited color array available in premixed products.

Owing in part to industry custom and the available colorant dispensing equipment, the custom color systems from different paint or stain manufacturers tend to have somewhat similar components. For example, a typical custom color paint system may employ several (e.g., 2 to 4) tintable base paints ranging for example from a bright white base that already contains a white pigment such as titanium dioxide and is intended to accept at most a small quantity of added colorant at the point-of-sale, to a relatively unpigmented clear base that is intended to accept a much larger quantity of added colorant at the point-of-sale. Base paints and stains may employ various binders (e.g., natural or synthetic resins), binder forms (e.g., solution polymers or latex polymers) and vehicles (e.g., solvent-borne or water-borne versions), and may provide various dried surface finishes (e.g., matte, semi-gloss or gloss finishes). Some manufacturers also sell colored base paints (e.g. a red, a blue and yellow colored base) which are intended to be combined with additional colorant(s) at the point-of-sale when strongly-tinted custom paint shades with one coat hiding power are desired.

Colorants for paints and stains in point-of-sale and in-plant tinting systems are most commonly supplied as liquid dispersions. The dispersion may for example be prepared by blending one or more raw pigment powders with a liquid carrier (for example, water or one or more organic solvents) along with surfactants, dispersion aides, biocides and other additives to provide a liquid colorant concentrate. Selected concentrates may be added in predetermined amounts to a base paint or stain to provide the final color shade. Liquid colorants are generally available in three types: water-only, solvent-based, and universal colorants designed to function in both water-borne and solvent-borne paints and stains. Universal colorants typically are formulated by modifying a liquid colorant formulation to include appropriate surfactants, and optionally to include appropriate dispersing agents or cosolvents, so that the colorant can tint either a water-borne or solvent-borne base paint or stain using the same tinting machine.

Solid colorants, also known as stir-in colorants, are available as an alternative to liquid colorants. Powdered colorants have been dispensed into paint in various ways, including as pourable powders (see e.g., the BASF XFAST™ line of powdered dry dosing colorants), and by using sachets or volumetric metering screw dispensers as discussed in González-Gómez et al., “Dry colour dispensing”, European Coatings Journal (June 2005, page 24). Powdered colorants can also be dispensed gravimetrically, as is done using BASF XFAST EASY COLOR™ powdered colorant canisters and the BASF HERO™ gravimetric colorant dispenser. Solid colorants are most commonly produced by spray-drying a liquid colorant formulation to provide a free-flowing, dry granular product. The asserted benefits for solid colorants versus liquid colorants have been said to include higher pigment concentration, longer shelf life, and ease-of-handling benefits such as lower bulk density and easier clean up. An important difference between liquid colorants and solid colorants is that solid colorants are at present generally available only in water-only and solvent-based forms. Despite attempts by manufacturers to produce and market a universal solid colorant line, satisfactory universal colorants are not presently available in solid form.

Years ago, paints and stains were virtually all solvent-borne. Although solvent-borne paints and stains continue to be used, nowadays 80% or more of architectural paints and a significant proportion of stains are water-borne. The overall percentage of water-borne paints and stains as a proportion of total sales is expected to continue to increase. Despite that, some workers or customers continue to prefer solvent-borne paints (for example, alkyd paints) or solvent-borne stains in some end-use applications, and may do so well into the future.

SUMMARY OF THE INVENTION

Unfortunately, the use of universal colorants requires compromises in paint performance in order effectively to bridge the colorant compatibility gap between water-borne and solvent-borne systems. For example, in water-borne paints tinted with universal colorants, the compromised performance factors may include one or more of higher volatile organic compound (VOC) content, surfactant leaching, increased tack, reduced blocking resistance and viscosity drop. For solvent-borne paints tinted with such colorants, the compromised performance factors may include one or more of longer drying time, reduced film hardness or altered gloss. Some point-of-sale paint stores use water-borne colorants to tint water-borne paints and stains, and employ a separate tinting machine containing solvent-borne colorants optimized for use with solvent-borne paints and stains. This solution is not ideal, since it requires investment in and maintenance of two tinting machines; requires the sale, storage and inventory of extra Stock Keeping Units (SKUs) representing the solvent-borne paint colorants; and may result in colorant shelf life expiration or dispenser plugging problems for less frequently used water-borne or solvent-borne colorants.

It would be desirable to provide a point-of-sale universal tinting system that could be used with either water-borne or solvent-borne paints and stains, without unduly compromising the performance of the resulting custom-tinted paint or stain products, and without requiring separate tinting machines and separate colorant arrays. We have found that by employing a paint tinting system utilizing water-borne and solvent-borne paint or stain bases, an array of powdered colorants usable in water-borne bases, and a synergist containing, primarily or exclusively, ingredients that will assist in dispersing the powdered colorants into solvent-borne paints or stains, we can reduce or eliminate the above-mentioned performance compromises, and avoid the need to purchase and maintain separate tinting machines and separate colorant arrays.

The synergist may be a liquid, powdered solid, or a dispersible solid object such as a compressed pill or tablet. The synergist may be introduced into a solvent-borne base paint or stain in a variety of ways, and may be introduced before, together with or (less preferably) after introduction of one or more powdered colorants into such solvent-borne base paint or stain. In one embodiment, the synergist may be supplied in a cartridge, canister or other standard container of the type normally used for liquid colorants and for some powdered colorants, disposed in one of the tinting machine dispenser slots normally reserved for a colorant, and dispensed into the base paint or stain using the tinting machine metering circuit. In another embodiment, the synergist may be dispensed into a solvent-borne base paint or stain using a separate, “bolt-on” dispensing system. Such a bolt-on system optionally may have lower precision than the tinting machine colorant metering circuit, as the amount of synergist to be employed does not need to be controlled as precisely as the colorant amount. In yet another embodiment, an in-store technician may separately add the synergist at the point-of-sale to a solvent-borne paint or stain (for example as a pill, tablet, sachet or other dispersible or dissolvable pouch, or as a pour-in powdered product). In a further embodiment, a paint or stain manufacturer may add or include the synergist to or in a base paint or stain at a factory, warehouse or other non-retail site prior to delivery to a point-of-sale retail, wholesale or combined retail/wholesale outlet. The system can accordingly be used with just the powdered colorants when it is desired to tint a water-borne paint or stain, and can be used with such colorants together with an appropriate amount of the synergist when it is desired to tint a solvent-borne paint or stain.

Because the synergist only needs to be used for tinting solvent-borne paints or stains, the ingredients (e.g., the cosolvents, dispersing agents or surfactants) in the synergist may be chosen to optimize the performance of the tinted solvent-borne paint or stain alone, and without regard to the potential impact on water-borne paint or stain performance.

The invention thus provides, in one aspect, a point-of-sale custom color system for tinting base paints and stains, the system comprising:

-   -   a) an array of powdered colorants including at least white,         green, blue and red colorants, the colorants being packaged in         containers from which colorant may be gravimetrically or         volumetrically dispensed via an automated or manual colorant         dispenser into the base paint or stain; and     -   b) at least one synergist containing, primarily or exclusively,         one or more ingredients that will disperse the powdered         colorants into solvent-borne base paints or stains.

In an embodiment, the above point-of-sale custom color system also includes at least one water-borne base paint or stain and at least one solvent-borne base paint or stain, the base paints or stains being packaged in largely but incompletely filled point-of-sale containers with a volume of about 0.2 to 20 L equipped with an openable and recloseable lid, cap or other closure for an opening through which colorant may be dispensed from the automated or manual colorant dispenser into the base paint or stain.

In a further embodiment, the above point-of-sale custom color system also includes the automated or manual colorant dispenser.

The invention provides, in another aspect, a point-of-sale custom color system for tinting base paints and stains, the system comprising:

-   -   a) an array of powdered colorants including at least white,         green, blue and red colorants, the colorants being packaged in         containers from which colorant may be gravimetrically or         volumetrically dispensed via an automated or manual colorant         dispenser into the base paint or stain; and     -   b) at least one water-borne base paint or stain and at least one         solvent-borne base paint or stain, the base paints or stains         being packaged in largely but incompletely filled point-of-sale         containers with a volume of about 0.2 to 20 L equipped with an         openable and recloseable lid, cap or other closure for an         opening through which colorant may be dispensed from the         automated or manual colorant dispenser into the base paint or         stain, wherein the solvent-borne base paint or stain includes a         synergist in the form of one or more ingredients that will         disperse the powdered colorants into such solvent-borne base         paint or stain.

In an embodiment, the latter point-of-sale custom color system also includes the automated or manual colorant dispenser.

The invention provides, in another aspect, a method for point-of-sale custom paint or stain tinting, the method comprising using an automated or manual colorant dispenser to dispense into water-borne and solvent-borne base paints or stains at a retail, wholesale or combined retail/wholesale outlet one or more powdered colorants selected from an array of colorants including at least white, black, red, green and blue powdered colorants, and further comprising adding to or including in the solvent-borne base paints or stains at least one synergist containing one or more ingredients that will disperse the powdered colorants into such solvent-borne base paints or stains.

The disclosed system and method permit point-of-sale formulation and sale of both water-borne and solvent-borne custom-tinted paints and stains using a single tinting machine and a single colorant array, while avoiding or minimizing added inventory, dedicated dispensers or dedicated floor space.

This application is related to copending U.S. Application Ser. No. 16/016,129, filed Jun. 22, 2018 and entitled “TINTING WATER-BORNE AND SOLVENT-BORNE PAINTS AND STAINS WITH WATER-ONLY COLORANTS”, the disclosure of which is incorporated herein by reference.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of an embodiment of the disclosed paint or stain tinting system;

FIG. 2 is a perspective view of guillotine valves for use in the dispenser shown in FIG. 1;

FIG. 3 is a schematic view of an embodiment of the disclosed colorant array and the disclosed synergist;

FIG. 4 is a schematic view of the addition to a container of a base paint or stain of a synergist in a sachet;

FIG. 5 is a schematic view of the addition to a container of a base paint or stain of a synergist from a squeeze bottle; and

FIG. 6 is a schematic view of the factory addition of a synergist to a solvent-borne base paint or stain, followed by shipment of the synergist-containing base paint or stain to a point-of-sale retail, wholesale or combined retail/wholesale outlet for subsequent tinting.

Like reference symbols in the various figures of the drawing indicate like elements. The elements in the drawing are not to scale.

DETAILED DESCRIPTION

Unless the context indicates otherwise the following terms shall have the following meaning and shall be applicable to the singular and plural:

The terms “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably. Thus, for example, a system or method that includes “a” synergist means that the system or method may include “one or more” synergists.

The terms “architectural paints” and “architectural stains” respectively mean paints and stains for use on interior or exterior building or construction surfaces, e.g., walls, trim, floors, decks, railings, ceilings, roofs (including metal roofing, shingles and tiles), roadways, sidewalks, etc.

The term “array” when used with respect to colorants means an assortment of colorants intended to be used individually or in appropriate combinations to tint base paints or stains so as to provide user-customized colors in a wide gamut of hues. A typical array will normally contain at least white, green, blue and red colorants, and usually will also contain one or more black colorants, one or more yellow colorants and one or more oxide colorants such as red oxide or yellow oxide. The individual colorants in a typical array will normally be supplied by a single manufacturer, be packaged in similar containers, bear similar labels each having a distinct SKU identifier, and may bear a unifying trademark for the array or for the brand of paint or stain with which the array is intended to be used.

The term “automated colorant dispenser” means a dispenser for paint or stain colorants which is controlled or controllable via electronically-regulated precision gravimetric weighing or volumetric metering devices so as to dispense controlled quantities of one or more colorants (e.g., powdered colorants) into a base paint or stain container and thereby facilitate preparation of tinted paints or stains whose tints are selected from an array of tints. The colorant types and amounts selected by such an automated colorant dispenser will optionally and preferably be controlled using software and a suitable database.

The term “base paint or stain” means a water-borne or solvent-borne paint or stain product packaged in a largely but incompletely filled point-of-sale container with a volume of about 0.2 to 20 L equipped with an openable and recloseable lid, cap or other closure, and which may be used as is but normally will be tinted at the point-of-sale by adding one or more colorants to the paint or stain product in its container, and stirring, shaking or otherwise mixing the container contents to disperse the colorant throughout the base paint or stain product.

The term “binder” means a film-forming natural or synthetic polymer suitable for use in a paint or stain.

The term “colorant” means a composition that can be added to (e.g., dispensed into) a point-of sale container whose interior volume is largely (e.g., two thirds of the container volume or more) but not completely already filled with a base paint or stain so as to alter the hue or lightness of such base paint or stain, and which contains pigment or dye and an optional surface treatment (e.g., a surfactant or dissolution aid) but is substantially free of binder.

The term “custom-tinted” when used with respect to a system or method for tinting base paints or stains means that one or more colorants can be dispensed into a base paint or stain and mixed to provide finished paint or stains in a wide variety of (e.g., more than one hundred or even more than one thousand) preselected formulated colors or, if desired, a match for randomly-selected colors. The preselected formulated colors will ordinarily be viewed by potential end users using printed color charts or displayed computer images.

The term “headspace” when used with respect to a base paint or stain in an openable container refers to an unfilled small portion of the total container volume (for example, about 1% to about 33%, and in some embodiments about 1% to about 15%, of the total container volume) available for and intended to be used for colorant addition.

The term “liquid” when used to describe a material that can exist in several different phases refers to the phase occupied by that material at room temperature (23° C.) and 1 atm.

The term “manual colorant dispenser” means a non-automated dispenser for paint or stain colorants that can manually meter quantities of one or more colorants into a base paint or stain container and thereby facilitate preparation of tinted paints or stains whose tints are selected from an array of tints.

The term “NVM” is an abbreviation for non-volatile materials, and refers to a material that does not significantly evaporate at standard temperature and pressure. NVM content may be evaluated using ASTM D1353-13.

The term “paint” means a coating composition including pigment and binder which when applied to form a thin (e.g., 100 μm) wet thickness coating film on a freshly-sanded smooth wood surface, will when dried hide or substantially hide the wood grain and will present a new surface with its own appearance.

The term “pigment” includes both colored, dispersible solid particulate materials and colored dispersible or soluble dye materials, wherein the material imparts visually noticeable color to a base paint or stain when 5 wt. % (in the case of a colored, dispersible solid particulate) or 0.05 wt. % (in the case of a colored, dispersible or soluble dye) of the material is added to (e.g., dispensed into) the base paint or stain. The presence or absence of visually noticeable color may be assessed by preparing drawdown samples of the base paint or stain with and without the pigment, casting such samples as 25 μm dry thickness coated films over the white part of a BYK-Gardner No. PA-2811 opacity drawdown chart (from BYK-Gardner USA) or comparable chart, and examining the coated films under normal overhead interior illumination.

The term “pigment volume concentration” when used in respect to a paint, stain or colorant means the total percentage of dried coating volume occupied by all pigment species in the coating.

The terms “point-of-sale” and “retail” when used with respect to a site, location, store or other outlet means a place at which custom-mixed paints or stains are tinted and mixed in small batch lots (e.g., one half pint, one pint, one quart, one liter, one gallon, four liter, five gallon or 20 liter containers, corresponding to containers from about 0.2 to 20 L) for sale to end-users (e.g., painters, builders and homeowners). Representative point-of-sale retail, wholesale or combined retail/wholesale outlets include paint stores, hardware stores, building supply stores (including warehouses), and distribution centers.

The term “powdered” when used with respect to a colorant means a solid, finely divided particulate material.

The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.

The term “primarily or exclusively”, when used with respect to the amount of an ingredient or ingredients in a synergist, means in the case of the word “primarily” that the named ingredient or ingredients represent at least 50 wt. % of the ingredients in such synergist. In some embodiments the named ingredient or ingredients may represent at least 60 wt. %, at least 70 wt. %, at least 80 wt. % or at least 90 wt. % of the ingredients in such synergist. In the case of the word “exclusively”, the synergist consists essentially of or consists of such named ingredient or ingredients.

The term “solid” when used to describe a material that can exist in several different phases refers to the phase occupied by that material at room temperature (23° C.) and 1 atm.

The term “solvent-borne” when used in respect to a paint or stain means that the major liquid vehicle or carrier for the paint or stain is a nonaqueous solvent or mixture of nonaqueous solvents.

The term “stain” means a coating composition including binder which when applied to form a thin (e.g., 100 μm) wet thickness coating film on a freshly-sanded smooth wood surface, will when dried not hide both the wood grain and its texture. When a semi-transparent stain is applied to wood, the wood grain and its texture normally both remain noticeable, whereas when a solid color (viz., opaque) stain is applied the grain normally becomes hidden while the texture normally remains noticeable. A stain typically will soak into a wood or other porous substrate (e.g., concrete) to a much greater extent than will a paint.

When used with respect to a component which may be found in a paint, stain or colorant composition, the term “substantially free of” means containing less than about 1 wt. % of the component based on the composition weight.

The terms “tint strength” and “tinting strength” refer to the value obtained using ASTM D 3022-84 (Reapproved 2005), Standard Test Method for Color and Strength of Color Pigments by use of a Miniature Sandmill, and calculated using the Kubelka-Monk equation for tinting strength set out in Section 8.4.4 of the ASTM Test Method. Preferably the measurements are obtained using spectrophotometric instrumentation such as Datacolor TOOLS™ software and a Datacolor SPECTRAFLASH™ SF300 or similar spectrophotometer, a D65 illuminant, CIE 1964 10° Standard Observer angle and reflectance mode.

The term “uncolored” when used with respect to a synergist means that the synergist does not contain visually noticeable quantities of pigment. A synergist may however have its own inherent color, such as the yellow coloration sometimes found in amine group-containing surfactants.

The term “water-borne” when used in respect to a paint or stain means that the major liquid vehicle or carrier for the paint or stain is water.

The term “water-only” when used with respect to a colorant means that the colorant can be used to tint a water-borne base paint or stain, but exhibits insufficient tint strength or objectionable rub-up (viz., unsatisfactory compatibility) when added by itself in an attempt to tint a conventional solvent-borne paint (such as Ace™ Royal™ polyurethane alkyd enamel from Ace Hardware Co., Item No. 245A320) or a conventional solvent-borne stain (such as Cabot™ Semi-Transparent deck and siding stain No. 0306 from The Valspar Corporation). Tint strength Rub-up may be evaluated using the Rub-Up Test shown below in the Examples section. Objectionable rub-up may for example correspond to less than a 6 pass score or more than a moderate dark rating in the Rub-Up Test. A skilled paint tinting technician would regard a water-only colorant as being a “non-universal” colorant, and would regard a universal colorant as not being a water-only colorant.

The recitation of a numerical range using endpoints includes all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

FIG. 1 shows a perspective view of an embodiment 100 of the disclosed paint and stain mixing system. Container 102 holds a liquid water-borne base paint or stain 104. The upper surface 106 (shown in phantom view) of base paint or stain 104 is located a sufficient distance D1 below container lid 108 so that a headspace 110 is available for the addition of one or more colorants to prepare a custom-tinted water-borne paint or stain with a custom hue. Handle 111 may be used to carry container 102. Container 112 holds a liquid solvent-borne base paint or stain 114. The upper surface 116 (also shown in phantom view) of base paint or stain 114 is located a sufficient distance D2 below container lid 118 so that a headspace 120 is available for the addition of one or more colorants to prepare a solvent-borne paint or stain with a custom hue. Distance D2 may be greater than, less than or the same as distance D1, and will depend on the amount of colorants already present in base paints or stains 104 and 114 and the expected amount of colorant(s) that might need to be dispensed into base paints or stains 104 and 114 to obtain satisfactory final hues. Handle 121 may be used to carry container 112. The disclosed system and method may optionally employ a further base or bases (not shown in FIG. 1), for example a clear water-borne or solvent-borne base paint or stain for making deep colored custom tints.

Base paint or stain containers 102 and 112 may be combined with colorant, and synergist may be added to solvent-borne base paint or stain 114, using powdered colorant dispenser 130. Dispenser 130 includes cabinet 132 on which is mounted shelf 134 where containers 102 or 112 may be placed for colorant addition, and in the case of container 112 for synergist addition. Rather than placing container 102 or 112 on shelf 134 for colorant addition, a small scoop, cup, tray, dish or other receptacle or platform such as cup 135 may be used to receive colorant from dispenser 130, followed by transfer of the dispensed colorant to container 102 or 112. Turntable 136 includes a series of refillable colorant or synergist dispenser canisters including canisters 138 a, 138 b, 138 c and 138 d containing a point-of-sale array of powdered colorants in most of the canisters and synergist in one or more of the remaining canisters. For example, the synergist may be contained in canister 138 a, and colorants may be contained in canisters 138 b, 138 c and 138 d and the other unnumbered canisters on turntable 136. Alternatively, for example if it is desired to use all available turntable positions for colorant addition, the synergist may be dispensed into solvent-borne base paint or stain 114 using a separate bolt-on dispenser. An exemplary such dispenser is represented by reservoir 152 which contains synergist 154 (shown in phantom view) and which is closed by removable cap 156. Reservoir 152 may be refilled by removing cap 156 and pouring additional synergist into reservoir 152. Outlet conduit 158, manually-operated valve 160 and dispensing spout 162 may be used to dispense synergist into container 112 from spout 164. The amount of synergist that has been added to container 112 may be estimated using index marks 166 or by noting the change in the content level within container 112 during synergist addition. The synergist volume may also be metered by valve 160, for example by providing a hollow chamber in valve 160 holding a specified amount (for example, 0.5 fluid ounce or 14.8 mL) and configuring valve 160 so that the entire contents of the chamber are dispensed from spout 164 when the handle on valve 160 is rotated one full turn. Additional turns can be used to dispense additional synergist. A typical synergist addition to a 1 gallon (3.78 L) base paint or stain container will be about 2 fluid ounces (about 59 mL), and need not be as precisely measured as when adding colorants. Thus for a valve 160 configured as described above, a single turn of the valve handle might be used to dispense sufficient synergist into a 1 quart (0.946 L) container holding a solvent-borne paint or stain, and four full turns might be used to dispense sufficient synergist into a 1 gallon (3.78 L) container holding such paint or stain.

When tinting a water-borne base paint or stain such as base paint or stain 104, the synergist preferably is not employed. When tinting a solvent-borne base paint or stain such as base paint or stain 114, the synergist is usually or always employed together with one or more colorants, and is omitted only when the volume or type of colorant is such that compatibility problems will not be expected to arise. The amount and type of synergist that will be dispensed into a solvent-borne base paint or stain may in the interest of simplicity be the same whenever a solvent-borne base paint or stain is tinted. In other embodiments, the amount or type of synergist(s) may be varied depending on the amount of colorant to be added (viz., more synergist or another synergist may be employed when a dark or deep tint is prepared, and less synergist or another synergist may be employed when a light pastel tint is prepared), the type of colorant to be added (viz., more synergist or another synergist may be employed when a green or blue tint is prepared, and less or no synergist may be employed when a black or yellow tint is prepared), or both the amount and type of colorant to be added. The amount or type of synergist(s) may also be varied depending upon the chosen solvent-borne base paint or stain. Preferably the synergist(s) are added prior to the addition of colorants, but this is not required.

FIG. 2 shows guillotine valves 202 and 204 with slide valve 206 (shown in its open position) and 208 (shown in its closed position) for controlling the flow of powdered colorant or synergist from dispenser canisters such as those shown in FIG. 1.

FIG. 3 is a perspective view of a point-of-sale colorant array 300 with thirteen containers 302 through 326 containing powdered colorants in different hues. In the center of FIG. 3 is a fourteenth container designated 328 and containing a synergist. Although not shown in FIG. 3, the corresponding point-of-sale custom color system will also include one or more water-borne paint or stain bases like base 102 in FIG. 1, and one or more solvent-borne paint or stain bases like base 112 in FIG. 1. Container 302 is representative of the other containers in FIG. 3, and may for example contain a conventional black powdered colorant such as a carbon black powder for use in tinting interior paints. Container 304 contains a different powdered colorant such as a non-infrared-absorptive black powdered colorant for use in tinting exterior paints. Containers 306 through 326 contain additional powdered colorants, which in the embodiment shown in FIG. 3 respectively are white, green, blue, red, magenta, red oxide, yellow oxide, medium yellow, yellow, transparent yellow and transparent red colorants. The colorants in containers 302 through 322 preferably are water-only powdered colorants optimized for use with water-borne paints and stains, and the colorants in containers 324 and 326 preferably are water-only powdered colorants optimized for use with water-borne stains. When added by themselves to a solvent-borne paint or stain, the colorants in containers 302 through 326 may exhibit poor compatibility. However, poor compatibility may not be exhibited by all such colorants. For example, the medium yellow colorant in container 320 and the yellow colorant in container 322 may, owing to the nature of these colorants, exhibit reasonable compatibility with both water-borne and solvent-borne paints and stains even in the absence of the synergist in container 328.

The synergist in container 328 preferably is optimized to provide improved compatibility (for example, a more homogeneous mixture and appearance, and one or both of increased tint strength and reduced rub-up) when at least colorants 306 through 312, and more preferably when each of colorants 302 through 318 and 324 through 326, is dispensed into a solvent-based paint or stain.

FIG. 4 is a schematic view of the addition to a container 402 containing a solvent-borne base paint or stain 404 of a synergist 406 in a plastic film sachet 408. Sachet 408 may be made from a variety of solvent-soluble materials such as polyvinylpyrrolidone/vinyl acetate copolymers. If desired, sachet 408 may be made from a material with solvent solubility but little or no water solubility so as to enable retrieval of the intact sachet if it is accidentally dropped into a container of a water-borne paint or stain. Sachet 408 may if desired be sized for use in a smaller (for example, 1 quart) standard container and multiple such sachets may be used when tinting the contents of a larger (for example, 1 gallon) standard container.

FIG. 5 is a schematic view of the addition to container 402 and solvent-borne base paint or stain 404 of a synergist 502 contained in a squeeze bottle 504. Index marks 506 or the contents level in container 402 may be used to gauge the amount of synergist added to container 402.

FIG. 6 is a schematic perspective view of a paint factory filling and packaging line 600 including conveyor 601 for transporting containers 602, which are largely but incompletely filled with solvent-borne base paint or stain 603, past filling station 604 where synergist 606 is added to paint or stain 603. In one embodiment, solvent-borne base paint or stain 603 does not contain any of the ingredients (e.g., surfactants) found in the synergist prior to the addition of synergist at filling station 604. In another embodiment, solvent-borne base paint or stain 603 may, prior to the addition of synergist at filling station 604, already contain one or more of the ingredients found in the synergist, but does not contain sufficient such ingredients to satisfactorily disperse powdered colorants from the array if added in amounts sufficient to fill the available headspace in container 602. Lids 610 are installed at capping station 612 and closed at pressing station 614. The resulting factory-filled, synergist-containing solvent-borne base paint or stain containers are shipped using for example truck 616 to a point-of-sale retail, wholesale or combined retail/wholesale outlet 620. At outlet 620, automated dispensing machine 622 equipped with a keyboard 624 and monitor 626 may be used to dispense powdered colorants through spout 628 into containers 606.

A variety of liquid base paints and stains may be used in the disclosed system and method, and will be familiar to persons having ordinary skill in the art. The base paints and stains normally will contain one or more polymeric binders and one or more pigments, and may in addition contain one or more vehicles or carriers and one or more adjuvants. Exemplary water-borne binders may for example include latex polymers and water-dispersible binders. Such water-dispersible binders may be water-dispersible as is, or may be water-dispersible following the addition of a suitable neutralizing agent such as ammonia or an amine. Exemplary solvent-borne binders may for example include solution polymers. Because appropriate chemical modifications may be used to convert a solution polymer to a water-dispersible polymer, is best to focus on polymer types broadly rather than categorizing any given polymer as being water-borne or solvent-borne. Representative binder polymers accordingly include but are not limited to acrylic copolymers, alkyd resins and other drying oil modified polymers including polyesters and polyurethanes, styrene/acrylic copolymers, vinyl acetate copolymers, vinyl acetate/acrylic copolymers, vinyl versatic acid ester/acrylic copolymers, ethylene/vinyl acetate copolymers, styrene/butadiene copolymers, polyesters, polyamides, epoxy esters, polyureas, polyurethanes, polysiloxanes, silicones, fluorinated copolymers such as vinylidene fluoride, and compatible blends of any of the above polymeric binders. The base paints or stains may include a component or components of a multicomponent (e.g., two component) reactive system for the binder such as a component of an isocyanate-polyamine, isocyanate-polyol, epoxy-polyamine, carbodiimide-polyacid, aziridine-polyacid, melamine-polyol, or urea formaldehyde-polyol system. The binder may for example represent about 5 to about 99 volume percent of the dried coating volume. The volume solids, as defined by the fractional volume of dry paint ingredients in the as-supplied wet base paint or stain, may for example represent about 5 to about 80 volume percent of the base paint. The glass transition temperature for the polymeric binder may for example be about −20 to about 60° C. The base paint or stain viscosity may for example be about 40 to about 140 Krebs units.

A variety of pigments may be employed in the base paints and stains, and will be familiar to persons having ordinary skill in the art. The pigments desirably form a stable dispersion that does not require agitation prior to use. In some instances a suitable pigment may also or instead be referred to commercially as a dye. Exemplary pigments include treated or untreated inorganic pigments and mixtures thereof, for example metallic oxides including titanium dioxide, iron oxides of various colors (including black) and zinc oxide; and metallic flakes such as aluminum flakes, pearlescent flakes, and the like. Exemplary pigments also or instead include treated or untreated organic pigments and mixtures thereof, for example carbon black, azo pigments, benzimidazolinones, carbazoles such as carbazole violet, indanthrones, isoindolinones, isoindolons, perylenes, phthalocyanines, quinacridones and thioindigio reds. Suitable pigments are commercially available from a variety of commercial suppliers including BASF, the LANXESS Inorganic Pigment Business Unit of Bayer Corp., Cabot Corp, Ciba Specialty Chemicals, Clariant, Ferro Corporation, Shepherd Color Company, Sun Chemical and Tomatec America, Inc. Other exemplary pigments are described, for example, in U.S. Pat. No. 8,141,599 B2 (Korenkiewicz et al.), U.S. Pat. No. 8,746,291 B2 (Hertz et al.), U.S. Pat. No. 8,748,550 B2 (Cavallin et al.) and U.S. Pat. No. 8,752,594 B2 (Gebhard et al.). The pigments are used in one or both of the base paint or stain and colorants in amounts sufficient to provide a suitably tinted and if need be suitably opaque cured final paint, stain or industrial coating at the desired coating thickness level, e.g., at pigment volume concentrations of about 0 to about 95 volume percent of the base paint or stain.

The pigments may be supplemented with extenders or fillers such as talc, china clay, barytes, carbonates, silicates and mixtures thereof, for example magnesium silicates, calcium carbonate, aluminosilicates, silica and various clays; organic materials including plastic beads (e.g., polystyrene or polyvinyl chloride beads), microspherical materials containing one or more voids, and vesiculated polymer particles (e.g., those discussed in U.S. Pat. Nos. 4,427,835, 4,920,160, 4,594,363, 4,469,825, 4,468,498, 4,880,842, 4,985,064, 5,157,084 5,041,464, 5,036,109, 5,409,776, and 5,510,422). Other exemplary extenders or fillers include EXPANCEL™ 551DE20 acrylonitrile/vinyl chloride expanded particles (from Expancel Inc.), SIL-CEL™ 43 glass micro cellular fillers (from Silbrico Corporation), FILLITE™ 100 ceramic spherical particles (from Trelleborg Fillite Inc.), SPHERICEL™ hollow glass spheres (from Potter Industries Inc.), 3M ceramic microspheres including grades G-200, G-400, G-600, G-800, W-210, W-410, and W-610 (from 3M), 3M hollow microspheres including 3M Performance Additives iM30K (also from 3M), INHANCE™ UH 1900 polyethylene particles (from Fluoro-Seal Inc.), and BIPHOR aluminum phosphate (from Bunge Fertilizantes S.A., Brazil).

Water-borne base paints or stains include water and optionally may include one or more cosolvents. The water may for example be tap water, deionized water or distilled water. Water-borne base paints or stains may for example contain sufficient water so that at least about 20 or at least about 35 and up to about 80 or up to about 65 wt. % solids are present when the tinted paint or stain is applied to a substrate. Cosolvents may assist in mixing or coating a water-borne base paint or stain; may speed up, retard or otherwise change the time or emissions associated with drying; may improve wet edge properties or overlap characteristics; may improve freeze-thaw protection, or may provide or improve other features, and generally will not be retained in a film of the dried, cured or otherwise hardened paint or stain. A chosen cosolvent may be a hazardous air pollutant solvent (HAPS material) but preferably is a non-HAPS material or is substantially free of HAPS materials. Exemplary cosolvents typically have low molecular weights (e.g., up to about 700, up to about 600, up to about 500 or up to about 400 g/mol) and may for example include glycols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol and propylene glycol), glycol ethers (e.g., DOWANOL™ DPM and Butyl CELLOSOLVE™ from Dow Chemical Co.), alcohols (e.g., methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-methyl butanol, isoamyl alcohol and other primary amyl alcohol isomers, n-pentanol, 2-ethylhexanol, 4-hydroxy-2,6,8-trimethylnonane and diisobutyl carbinol), esters and ester alcohols (e.g., isopropyl acetate; n-butyl acetate; isobutyl acetate; n-propyl acetate; primary amyl acetate mixed isomers, and UCAR™ Ester EEP from Dow Chemical Co.), ketones (e.g., diisobutyl ketone and ECOSOFT™ Solvent IK from Dow Chemical Co.), CARBOWAX™ 300 and CARBOWAX 600 polyethylene from Dow Chemical Co., mixtures thereof and the like. When a cosolvent is present, the coating compositions may for example contain at least about 0.1 or at least about 2 wt. % cosolvent and up to about 10 or up to about 5 wt. % cosolvent based on the tinted paint or stain weight.

The disclosed water-borne base paints and stains preferably are low VOC solutions or dispersions. They may for example contain zero to less than 8 wt. % VOCs, more preferably less than 6 wt. % VOCs, yet more preferably less than 4 wt. % VOCs, and most preferably less than 2 wt. % VOCs based upon the total liquid composition weight.

Solvent-borne base paints or stains may include one or more solvents. The solvent may function as a carrier for the other components of the base paint or stain or may facilitate the blending of colorants or additional ingredients into the base paint or stain. The chosen solvent may depend in part on the chemical makeup of the base paint or stain binder. Exemplary solvents include aliphatic and aromatic solvents, such as mineral spirits, xylene, ketones, glycol ethers, organic esters, alcohols, ethylene or propylene glycols and other aromatic compounds. Mixtures of solvents may be employed, for example, aromatic distillates may be combined with glycol ethers or alcohols. A solvent-borne base paint or stain may for example contain at least about 20 or at least about 30 wt. % solvent, and up to about 50 or up to about 45 wt. % solvent based on the total composition weight.

An optional reactive diluent or resin may be included in the base paint or stain. The reactive diluent or resin may function as a carrier for the other components of the base paint or stain, may facilitate the blending of colorants or additional ingredients into the base paint or stain, may increase the solids content at application without increasing the coating viscosity or VOC content, or may enhance (in some cases, synergistically) various coating performance characteristics such as adhesion, hardness and chemical resistance. Suitable reactive diluents or resins include polymerizable monomers (for example, acrylic or methacrylic monomers), vinyl resins, acrylic resins, epoxy resins, oligomers, polyether polyols, and a variety of low molecular weight polyfunctional resins. If employed, a reactive diluent or resin may for example represent at least about 0.1, at least about 0.5 or at least about 1 wt. %, and up to about 20, up to about 15 or up to about 10 wt. % based on the weight of ingredients in the tinted paint or stain.

Water-borne base paints or stains typically will contain one or more dispersing agents and one or more surfactants. Exemplary dispersing agents include anionic polyelectrolyte dispersants such as maleic acid copolymers, acrylic acid copolymers including methacrylic acid copolymers, and carboxylic acids such as tartaric acid, succinic acid, citric acid, itaconic acid, mixtures thereof and other materials that will be familiar to persons having ordinary skill in the art. Exemplary surfactants include anionic, amphoteric and nonionic materials. There may be some overlap in nomenclature when certain dispersants or surfactants are identified in commercial literature. Suitable dispersants and surfactants are commercially available from a variety of suppliers including 3M, Air Products and Chemicals, Inc., Akzo Nobel, Ashland, BASF, Dow Chemical Co., E. I. DuPont de Nemours and Co., Elementis Specialties, Inc., Harcros Chemicals, Rhodia and Solvay, such as the TAMOL™ series from Dow Chemical Co., nonyl and octyl phenol ethoxylates from Dow Chemical Co. (e.g., TRITON™ X-45, TRITON X-100, TRITON X-114, TRITON X-165, TRITON X-305 and TRITON X-405) and other suppliers (e.g., the T-DET N series from Harcros Chemicals), alkyl phenol ethoxylate (APE) replacements from Dow Chemical Co., Elementis Specialties, Inc. and others, various members of the SURFYNOL™ series from Air Products and Chemicals, Inc. (e.g., SURFYNOL 104, SURFYNOL 104A, SURFYNOL 104BC, SURFYNOL 104DPM, SURFYNOL 104E, SURFYNOL 104H, SURFYNOL 104PA, SURFYNOL 104PG50, SURFYNOL 104S, SURFYNOL 2502, SURFYNOL 420, SURFYNOL 440, SURFYNOL 465, SURFYNOL 485. SURFYNOL 485W, SURFYNOL 82, SURFYNOL CT-211, SURFYNOL CT-221, SURFYNOL OP-340, SURFYNOL PSA204, SURFYNOL PSA216, SURFYNOL PSA336, SURFYNOL SE and SURFYNOL SE-F), various fluorocarbon surfactants from 3M, E. I. DuPont de Nemours and Co. and other suppliers, and phosphate esters from Ashland, Rhodia and other suppliers. When a surfactant or dispersant is present, the base paint or stain may for example contain at least about 0.1, at least about 0.5 or at least about 1 wt. % surfactants or dispersants, and up to about 10, up to about 5 or up to about 3 wt. % surfactants or dispersants based on the total composition weight.

The base paint or stain may contain a variety of other adjuvants that will be familiar to persons having ordinary skill in the art. Representative adjuvants are described in Koleske et al., Paint and Coatings Industry, April, 2003, pages 12-86. Exemplary adjuvants and commercial examples of the same include anti-cratering agents; biocides, fungicides, mildewcides and preservatives (e.g., BUSAN™ 1292 from Buckman Laboratories, Inc., NOPCOCIDE™ N-40D from Cognis, KATHON™ LX from Rohm & Haas, and POLYPHASE™ 663, POLYPHASE 678 and POLYPHASE PW-40 from Troy Corporation); coalescing agents (e.g., those described in U.S. Pat. No. 8,110,624 B2 to Brandenburger et al.); curing indicators; heat stabilizers; leveling agents; light stabilizers (e.g., hindered amine light stabilizers such as TINUVIN™ 123-DW and TINUVIN 292 HP from Ciba Specialty Chemicals); optical brighteners; ultraviolet light absorbers (e.g., TINUVIN 234 and TINUVIN 1130 from Ciba Specialty Chemicals); wetting agents (e.g., BYK™ 346 and BYK 348 from Altana, PENTEX™ 99 from Rhodia and TROYSOL LAC™ from Troy corporation); waxes (e.g., AQUACER™ 593 from Altana, HYDROCER™ 303 from Shamrock Technologies, Inc. and MICHEM™ Emulsion 32535 from Michelman, Inc.); and the like. The types and amounts of these and other adjuvants typically will be empirically selected.

Exemplary commercially-available water-borne base paints and stains that can be used in the disclosed system include ARMSTEAD™, CORAL™, DULUX™ TRADE™ and FLEXA™ emulsion paints from Akzo Nobel; BEHR™, BEHR MARQUEE™ and BEHR PREMIUM™, PREMIUM PLUS™ and PREMIUM PLUS ULTRA™ latex paints from Behr Process Corporation; BENJAMIN MOORE™, BENJAMIN MOORE ADVANCE™, BENJAMIN MOORE AURA™, BENJAMIN MOORE BEN™, BENJAMIN MOORE NATURA™ and BENJAMIN MOORE SELECT™ latex paints from Benjamin Moore & Co.; GLIDDEN™, GLIDDEN PREMIUM™, GLIDDEN HIGH ENDURANCE™, GLIDDEN SPRED™, GLIDDEN DIAMOND™, MANOR HALL™, PORTER™, REGENCY™, WONDER-PURE™ and WONDER-TONES™ latex paints from PPG Industries, Inc.; A-100™, DURATION™, EMERALD™, INFINITY™, OVATION™, RESILIENCE™, SHERWIN-WILLIAMS™, SHOWCASE™ and SUPERPAINT™ latex paints and MINWAX™ Water Based Wood Stains from Sherwin-Williams; and DURAMAX™, MEDALLION, OPTIMUS™, PRISTINE™, RESERVE™, SIGNATURE™, ULTRA™, and VALSPAR™ latex paints from The Valspar Corporation.

Exemplary commercially-available solvent-borne base paints and stains that can be used in the disclosed system include GREAT FINISHES™ stains from Ace Hardware Corporation; DULUX™ and (outside the U.S.) GIDDEN™ alkyd paints from Akzo Nobel; BEHR™ alkyd paints from Behr Process Corporation; oil-based stains from McCormick Paints; MOORE SATIN IMPERVO™ alkyd paint from Benjamin Moore & Co.; WEATHER-SHIELD™ alkyd paints from Kelly-Moore Co., alkyd paints from Huaron Paints (China); BAR-OX™, VELOUR™ and (outside the US) GLIDDEN™ alkyd paints from PPG Industries, Inc.; SHERWIN-WILLIAMS PROCLASSIC™ alkyd paints and MINWAX and MINWAX WOOD FINISH™ stains from Sherwin-Williams; VALSPAR ULTRA 4000™ alkyd paint and CABOT™ stains from The Valspar Corporation; and PERMO-PAVE™ alkyd paints from Wattyl Australia Pty. Ltd.

The base paints and stains typically will be packaged in containers suitable for point-of-sale mixing of small batch lots in custom colors and subsequent sale in the same container to the end user of a custom-tinted paint or stain. Exemplary small batch lot base paint or stain container sizes are about one half pint, one pint, one quart, one liter, one gallon, four liter, five gallon or 20 liter containers, corresponding to base paint or stain containers from about 0.2 to 20 L. The base paint or stain container typically will be equipped with a removable lid, cap or other closure for an opening through which colorant may be dispensed into the base paint or stain. Depending on the amount of pigment already present in a base paint or stain, the base paint or stain container typically will have a small headspace (e.g., about 1 to about 15% of the container volume) for colorant addition. For example, a nominal one gallon (3.79 L) clear base paint or stain container may hold up to about 112 fluid ounces (3.31 L) or up to about 116 fluid ounces (3.43 L) of the base paint or stain, respectively leaving at least about 16 fluid ounces (0.47 L or about 13% of the total container volume) or at least about 12 fluid ounces (0.35 L or about 9% of the total container volume) available for colorant addition. A nominal one gallon (3.79 L) white base paint or stain container may for example hold about 128 fluid ounces (3.79 L) of the base paint or stain, with only a small headspace (e.g., about 0.04 L or about 1% of the total container volume) available for colorant addition. When additional base paints or stains of intermediate lightness are employed, they likewise may have intermediate available headspace volumes for colorant addition. For example, a three base system may employ the white and clear base paints or stains mentioned above, together with a gray base whose container has up to about 120 fluid ounces (3.55 L) or up to about 124 fluid ounces (3.57 L) of base paint or stain with at least about 8 fluid ounces (0.24 L) or at least about 4 fluid ounces (0.12 L) of headspace available for colorant addition. Additional high chroma base paints or stains (e.g., deep red, deep blue or deep yellow base paints or stains) may be employed if desired for making strongly-tinted custom paint shades with potential one coat hiding power.

A variety of powdered colorants may be used in the disclosed system and method, and will be familiar to persons having ordinary skill in the art. The colorants normally will contain one or more powdered pigments and one or more pigment dispersing agents or surfactants, and typically will have been produced by spray-drying a slurry or solution containing the colorant ingredients. Suitable pigments for use in the colorants include those discussed above. Colorants or colorant arrays containing entirely inorganic pigments or pigment mixtures may be preferred where custom-tinted paints or stains having maximum exterior durability are desired. Suitable pigment dispersing agents and surfactants include those discussed above. The colorant may for example contain at least about 10, at least about 20 or at least about 30 wt. % pigment and up to about 95, up to about 90 or up to about 85 wt. % pigment. The colorant may for example contain at least about 5, at least about 10 or at least about 15 wt. % surfactants or dispersants, and up to about 90, up to about 80 or up to about 70 wt. % surfactants or dispersants based on the total colorant weight. The colorants may also contain one or more adjuvants. Suitable adjuvants include those discussed above. The finished colorants typically will not contain water, solvents, or film-forming binders, and should be combined with a base paint or stain in order to provide a durable dried or cured finish. The colorants preferably are dry, finely-divided, free-flowing, pourable low dusting powders that can be stirred into or otherwise easily mixed with aqueous coating formulations such as water-borne paints and stains without clumping or undesirable settling or separation.

Exemplary powdered colorants that may be used in the disclosed system are or have been produced by a number of manufacturers including BASF and Clariant, such as the XFAST POS and XFAST EASY COLOR lines from BASF. Exemplary individual powdered colorants include organic powdered pigments such as XFAST Green 8730 (80 wt. % PG 7), XFAST Red 3860 (80 wt. % PR 254), XFAST Yellow EH 2420 (1256) (75 wt. % PY 74), XFAST Black 0063 (70 wt. % PBK 7), XFAST Blue 7081 (40 wt. % PB 15:3), XFAST Black 0062 (10 wt. % PBK 7), XFAST Orange 2931 (PO 67), XFAST Red 3750 (20 wt. % PR 168), XFAST Red 3861 (10 wt. % PR 254), XFAST Magenta 4791 (30 wt. % PR 122), XFAST Violet 5880 (10 wt. % PV 23) and XFAST Yellow 1260 (70 wt. % PY 154), inorganic powdered pigments such as XFAST Blue ED 7905 (6310) (80 wt. % PB 28), XFAST Black 0050 (80 wt. % PBK 11), XFAST Black 0095 (80 wt. % PBR 29), XFAST Green 9990 (80 wt. % PG 17), XFAST Brown EH 0290 (2900) (76 wt. % PR 101), XFAST Red 2817 (60 wt. % PR 101), XFAST Red 3390 (80 wt. % PR 101), XFAST White 0025 (85 wt. % PW 6), XFAST Yellow 1916 (60 wt. % PY 42), XFAST Yellow 1990 (80 wt. % PY 42), XFAST Yellow 1102 (80 wt. % PY 184) and XFAST Yellow 1130 (80 wt. % PY 184), and mixtures thereof. The chosen colorants may include all or a portion of a particular product array. For example, an array of powdered colorants including at least white, green, blue and red colorants may be selected from the above-mentioned XFAST product line by selecting XFAST White 0025, XFAST Green 8730, XFAST Blue 7081, and XFAST Red 3860 or 3861 for interior applications and XFAST Red 2817, 3390 or 3750 for exterior applications. Additional colorants may, subject to the availability of suitable dispenser slots, be added to the array as desired. Exemplary such additional colorants include one or more yellow, orange, magenta, brown or black colorants such as the BASF colorants mentioned above.

The disclosed system and method may for example employ 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 colorants, but may employ as few as four colorants if a restricted (viz., relatively few hues and relatively low gamut) color space is acceptable. The disclosed system may employ more than 15 colorants if sufficient dispenser slots are available and additional colorant SKUs are acceptable. For example, the disclosed system and method may employ 16, 17, 18, 19, 20, 21, 22, 23 or 24 colorants.

When the available number of colorant dispenser canisters is limited (e.g., when using a 12 or fewer canister dispenser), the number of colorant SKUs may be reduced by recognizing that some individual colorants are themselves mixtures of pigments which may be replaced with a precisely-metered blend of individual colorants. For example, many custom color paint systems employ one or more earth-tone colorants variously referred to using names such as brown oxide, raw umber or umber. Although brown oxide colorant is sometimes referred to as being made from a single pigment (e.g., PBr7 natural iron oxide), it may actually have been made using a blend of red and yellow oxides (e.g., PR101 red iron oxide and PY42 yellow iron oxide) shaded with carbon black (e.g., PBk7 carbon black) to match a specific color target. Raw umber or umber earth-tone colorants (which may collectively be referred to as “raw umber” colorants) likewise may have been made from a blend of colored oxides and carbon black. These blends may be replaced by adding colorants wholly made from (or substantially wholly made from) appropriate individual pigments, so as to provide a paint or stain whose coloration is like the coloration that would be obtained using a traditional blended pigment colorant. This may be done by using an automated colorant dispenser having a suitably low minimum dispensing quantity (e.g., a minimum dispensing quantity less than 0.005 g) so as to enable dispensing small quantities of the individual colorants. For example, a blend made using precisely-measured small amounts of yellow oxide pigment, red oxide pigment and black pigment may be dispensed into the base paint or stain whenever a tinted paint or stain with a brown oxide or raw umber tint is required.

The amount of colorant(s) dispensed into a 1 gallon (3.78 L) nominal container of base paint or stain will vary in part depending on the base paint or stain PVC values and may for example range from about 0.0001 g to about 300 g of colorant addition, with larger amounts typically being employed in a clear base paint or stain or in a larger base paint or stain container, and smaller amounts typically being employed in a white base paint or stain or in a smaller base paint or stain container. The finished tinted paints or stains may for example have PVC values of at least about 0.5 or at least about 1 vol. %, and may for example have PVC values of up to about 85 vol. % or up to about 50 vol. %.

The colorant array may if desired include one or more liquid colorants (e.g., one or more water-borne or solvent-borne colorants). Preferably however, all of the colorants in the array and in the colorant dispenser are powdered colorants. In one preferred embodiment, the majority or even all of the colorants in the array and in the colorant dispenser are water-only colorants. In other preferred embodiments, less than two, less than one or none of the colorants in the array and in the colorant dispenser are compatible with alkyd paints and stains, and the remaining colorants in the array will exhibit insufficient tint strength or visually objectionable rub-up if dispensed into such alkyd paints and stains without the synergist in representative tinting amounts of about 1 to about 15% of the alkyd paint or stain weight.

The colorants (and optionally the synergist) typically will be packaged in containers suitable for use in the chosen colorant dispenser(s), and sold to the dispenser owner or operator in a point-of-sale custom tinting facility, or if desired to end users of custom-tinted paints or stains. Expressed gravimetrically, exemplary small batch lot colorant container sizes are at least about 100, 250, 500, 750 or 1,000 grams; and up to about 2, 3, 4 or more kilograms. Exemplary colorant containers include boxes, cans, cartridges, jars, pails, pouches (e.g., sealed pouches made of metal or plastic) and other containers in which the colorant can be sealed for storage and shipment and, when needed to replace an empty container, placed in an appropriate slot or other receptacle or poured into an appropriate hopper or other vessel in the colorant dispenser so that colorant may be dispensed by the colorant dispenser in controlled amounts. The colorants may be supplied to the dispenser owner or operator in a can or other sealed container designed to be opened using a can opener or other can-puncturing device. The containers may be equipped with a manually-openable closure such as an openable and recloseable cap, or may be equipped with an irreversibly openable closure such as a tear-off seal or rupturable septum. In any event, once the container has been opened, colorant may be supplied to the colorant dispenser and thence into the base paint or stain container. Desirably the container, colorant dispenser or both have a tapered base with sloping sides terminating in a spout or other orifice which facilitates clean flow of the colorant out of the container and into and through the colorant dispenser with minimal spillage or waste before or after use. As supplied to the dispenser owner or operator, the colorant container may if desired include little or no headspace.

A variety of cosolvents, dispersing agents or surfactants may be used in the disclosed synergist. Exemplary such materials include cosolvents, dispersing agents or surfactants that have been used or recommended for use in universal paint colorants, such as those described in U.S. Pat. No. 2,878,135 (Willis), U.S. Pat. No. 6,287,377 B1 (Binns et al.), U.S. Pat. No. 7,659,340 B2 (Coward et al.), U.S. Pat. No. 9,080,030 B2 (Amiel et al.), U.S. Patent Application Publication No. US 2016/0333213 A1 (Zhou et al.) and Published International Application No. WO2016040641 A1 (Donlon et al.). In certain preferred embodiments the synergist will be a combination of two or more cosolvents, two or more dispersing agents or two or more surfactants, with the combination being selected to provide improved colorant compatibility across a range of solvent-borne base paint or stain binders, or within an array of powdered colorants. In some embodiments the synergist may contain both one or more cosolvents and one or more dispersing agents; both one or more cosolvents and one or more surfactants; both one or more dispersing agents and one or more surfactants; or each of one or more cosolvents, one or more dispersing agents and one or more surfactants. As will be appreciated by persons having ordinary skill in the art, the cosolvents will be liquids, and preferably low VOC liquids. In some embodiments, cosolvents used as synergists will have low molecular weights (e.g., up to about 200, up to about 150, up to about 125 or up to about 100 g/mol). As will be appreciated by persons having ordinary skill in the art, the dispersing agents and surfactants may be solids or liquids. When solid dispersing agents or solid surfactants are employed, they may if desired be combined with one or more liquid ingredients (preferably a low VOC ingredient) to provide a liquid synergist.

Suitable synergists may be selected in a variety of ways, including empirical testing to identify cosolvents, dispersing agents or surfactants that render the individual members of the desired powdered colorant array compatible with the desired base paints and stains; by selecting cosolvents, dispersing agents or surfactants that have previously been used in universal colorants; or by choosing cosolvents, dispersing agents or surfactants based upon structural considerations such as hydrophilicity, oliophilicity and the ability of the synergist to pull a powdered colorant into a solvent phase.

Exemplary cosolvents for use in the disclosed synergist include the cosolvents discussed above. Glycols (e.g., ethylene glycol and diethylene glycol), glycol ethers (e.g., DOWANOL™ DPM and Butyl CELLOSOLVE™ from Dow Chemical Co.), alcohols (e.g., n-propanol, isopropanol, n-butanol, isobutanol, 2-methyl butanol, isoamyl alcohol and other primary amyl alcohol isomers, n-pentanol, 2-ethylhexanol, 4-hydroxy-2,6,8-trimethylnonane and diisobutyl carbinol), esters and ester alcohols (e.g., isopropyl acetate; n-butyl acetate; isobutyl acetate; n-propyl acetate; primary amyl acetate mixed isomers, and UCAR™ Ester EEP from Dow Chemical Co.) represent preferred cosolvents, and ethylene glycol and diethylene glycol represent especially preferred cosolvents. The cosolvents preferably are (but in view of their intended use in solvent-borne base paints and stains are not required to be) low VOC materials.

Exemplary dispersing agents for use in the disclosed synergist include monomeric, oligomeric or polymeric materials that may assist in dispersing the colorant pigments into solvent-borne base paints and stains. The dispersing agents preferably are (but in view of their intended use in solvent-borne base paints and stains are not required to be) low VOC materials. There may be some overlap in materials that may be designated as dispersing agents for use in or as the disclosed synergist and materials that may have been designated in other contexts for use as cosolvents. With that in mind, exemplary dispersing agents that may be used in or as the synergist include materials such as dioctyl maleate, tributyl citrate, dihydric or polyhydric alcohols, polyethers including polyalkyl glycols and polyhydroxyethers, alcohols including ester alcohols such as TEXANOL™ ester alcohol from Eastman Chemical Company, modified polyureas, polyalkylene oxides, combinations thereof, and compounds having the formula I shown below: R₁O(C(O))_(m)A(R₃)(R₄)(C(O))_(n)R₂  I

-   -   wherein: A is a divalent C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl or C₃-C₁₀         cycloalkyl radical;     -   R₃ and R₄ are independently H, substituted or unsubstituted         C₁-C₆ alkyl, substituted or unsubstituted C₃-C₆ cycloalkyl, —OR₅         or C(O)OR₅ radicals, wherein R₅ is H or a substituted or         unsubstituted C₁-C₆ alkyl, substituted or unsubstituted C₃-C₆         cycloalkyl, or C₁-C₆ alkoxy radical;     -   R₁ and R₂ are independently H, —C═O, or a substituted or         unsubstituted C₁-C₆ alkyl radical;     -   m is 0 or 1; and     -   n is 0 or 1.

Exemplary compounds of Formula I include the compounds II and III shown below:

Exemplary surfactants for use in the disclosed synergist include nonionic, anionic, cationic or amphoteric surfactants. Nonionic surfactants are presently preferred. Anionic, cationic or amphoteric surfactants may be used with some water-only colorants, especially if used in combination with one or more other synergists. Set out below in Table I are a variety of exemplary surfactants for use in the disclosed synergist formulations, along with an identification of their physical form at room temperature and an indication of their compatibility with alkyd or latex paints. Those shown as being compatible with both alkyd and latex paints may in many instances be used as is. Those that are shown as being compatible only with alkyd paints but not with latex paints may also in many instances be used as is. Those however that are shown as being compatible only with latex paints but not with alkyd paints should be used together with one or more alkyd-compatible surfactants, which normally would be located in the synergist rather than in the colorants. In preferred embodiments, the synergist formulations comprise, consist of or consist essentially of at least one liquid surfactant from Table I, or a combination of liquid and solid surfactants from Table I that when mixed will provide a liquid dispensable from a canister in a tinting machine. Additional preferred embodiments are also solvent-free and thereby provide low to zero VOC formulations:

TABLE I Physical Alkyd Latex Item Description Form Compat. Compat. YELKIN ™ TS Soya lecithin liquid x Lecithin Unbleached (from Archer Daniels Midland Co.) HYDROPALAT ™ difunctional block liquid x WE 3135 (from copolymer BASF) terminating in primary hydroxyl groups HYDROPALAT WE difunctional block liquid x 3167 (from BASF) copolymer terminating in primary hydroxyl groups HYDROPALAT WE difunctional block liquid x 3317 (from BASF) copolymer terminating in primary hydroxyl groups TETRONIC ™ 904 tetrafunctional block paste x (from BASF) copolymer terminating in primary hydroxyl groups BYK ™ 2015 (from solution of a liquid x Byk Altana) structured acrylate copolymer with pigment affinic groups DISPERBYK ™ 102 copolymer with liquid x x (from Byk Altana) acidic groups DISPERBYK 190 solution of a high liquid x (from Byk Altana) molecular weight solution block copolymer with pigment affinic groups DISPERBYK 2091 modified liquid x x (from Byk Altana) polyalkoxylate with neutral pigment affinic groups DISPERBYK 2095 salt polyamine liquid x x (from Byk Altana) amides and polyesters CENTROLEX F ™ oil-free dry lecithin Solid x powder (from Central Soya Company Inc.) HOSTAPHAT ™ 1306 phosphate ester liquid x x (from Clariant) SMA 1440H (from styrene maleic liquid x x Cray Valley) anhydride copolymer solution solution AEROSOL ™ OT-100 sodium dioctyl solid x x (from Cytec Industries) sulfosuccinate TAMOL ™ 165A hydrophobic liquid x Dispersant (from Dow copolymer Chemical Company) polyelectrolyte TAMOL 731A 25% Na salt of a maleic liquid x (from Dow Chemical anhydride copolymer solution Company) TERGITOL ™ 15-S-9 secondary alcohol liquid x x Surfactant (from Dow ethoxylate Chemical Company) SOLEC ™ F Deoiled dry lecithin solid x Soy Lecithin Powder (from DuPont Danisco) TEGO ™ Dispersant solution of a liquid x 750 W (from Evonik copolymer with solution Resource Efficiency pigment affinic GmbH) groups SOLSPERSE ™ 67000 100% NVM liquid x x (from Lubrizol Corp) polymeric compatibiliser ABEX ™ 2545 (from proprietary nonionic liquid x Rhodia Solvay Group) surfactant GEROPON ™ 99 sodium dioctyl liquid x x (from Rhodia Solvay sulfosuccinate Group) (Solvay) GEROPON AS-200 sodium cocoyl solid x x flake (from Rhodia isethionate Solvay Group) GEROPON SDS sodium dioctyl solid x x (from Rhodia Solvay sulfosuccinate Group) GEROPON T-22A sodium methyl oleyl liquid x x (from Rhodia Solvay taurate Group) GEROPON T-77 sodium oleyl N- solid x x (from Rhodia Solvay methyl taurate Group) LUBRHOPHOS ™ LK linear alcohol ethoxy liquid x x 500 (from Rhodia phosphate Solvay Group) NOVEL ™ 23E7 alcohol ethoxylate liquid x x Ethoxylate (from Rhodia Solvay Group) NOVEL 23E9 alcohol ethoxylate liquid x x Ethoxylate (from Rhodia Solvay Group) PENTEX ™ 99 (from sodium dioctyl liquid x x Rhodia Solvay Group) sulfosuccinate RHODACAL ™ 330 branched liquid x x (from Rhodia Solvay isopropylamine Group) dodecylbenzene sulfonate RHODACAL BX-78 sodium dibutyl solid x x (from Rhodia Solvay naphthalene Group) sulfonate RHODACAL DS-10 branched sodium solid x x (from Rhodia Solvay dodecylbenzene Group) sulfonate RHODACAL IPAM linear liquid x (from Rhodia Solvay isopropylamine Group) dodecylbenzene sulfonate RHODACAL N (from sulfonated solid x x Rhodia Solvay Group) naphthalene condensate, sodium salt RHODACAL SSA/A linear sodium liquid x x (from Rhodia Solvay dodecylbenzene Group) sulfonate RHODAFAC ™ PL-6 linear alcohol ethoxy liquid x x (from Rhodia Solvay phosphate Group) RHODAFAC PL-620 linear alcohol ethoxy liquid x x (from Rhodia Solvay phosphate Group) RHODAFAC RA-600 linear alcohol ethoxy liquid x x (from Rhodia Solvay phosphate Group) RHODAFAC RS-410 branched alcohol liquid x x (from Rhodia Solvay ethoxy phosphate Group) RHODAFAC RS-610 branched alcohol liquid x x (from Rhodia Solvay ethoxy phosphate Group) RHODAFAC RS-710 branched alcohol liquid x (from Rhodia Solvay ethyoxy phosphate Group) ester RHODAFAC RS-960 branched alcohol liquid x x (from Rhodia Solvay ethoxy phosphate Group) RHODASURF ™ BC- dodecylphenol liquid x x 630 (from Rhodia ethoxylate Solvay Group) RHODASURF BC- tridecyl alcohol liquid x x 720 (from Rhodia ethoxylate Solvay Group) RHODOLINE ™ 3600 100% NVM liquid x x (from Rhodia Solvay proprietary Group) compatibiliser RHODOLINE proprietary liquid x x DP5817 (from Rhodia compatibiliser Solvay Group) SOPROPHOR ™ tristyrylphenol liquid x x 3D/33 (from Rhodia ethoxy phosphate Solvay Group) SOPROPHOR TS-10 ethoxylated liquid x x (from Rhodia Solvay tristyrylphenol Group) G-3300 Alkyl Aryl alkyl aryl sulfonate, liquid x Sulfonate (from isopropyl amine salt Stepan Company)

The disclosed synergist may if desired include one or more adjuvants, such as one or more rheology modifiers or thickeners. Other optional adjuvants include but are not limited to adhesion promoters, antioxidants, biocides, buffers, coalescing agents, defoamers, dispersants, dyes, extender fillers, humectants, leveling agents, neutralizers, optical brighteners, pearlescents, plasticizers, polymeric additives, preservatives, reactive diluents, tackifiers, ultraviolet stabilizers (e.g., hindered amine light stabilizers) and waxes. The synergist may in some embodiments include water, in amounts for example of at least about 110 wt. %, at least about 125 wt. %, or at least about 150 wt. % of the weight of nonaqueous ingredients in the synergist, and in amounts up to about 500 wt. %, up to about 400 wt. % or up to about 300 wt. % of the weight of nonaqueous ingredients in the synergist. In certain embodiments, the disclosed synergist consists essentially of or consists of cosolvents, optional dispersing agents, optional surfactants and optional rheology modifiers or thickeners. For example, the synergist may contain less than 5 wt. % or less than 1 wt. % of any other ingredients.

The synergist may be packaged and shipped in a variety of containers, including those discussed above in connection with the base paint or stain, and those discussed above in connection with the colorant. In some embodiments, the synergist container is like that used for the colorants, and can be installed in and dispensed from an available slot in the colorant dispenser. In other embodiments, the synergist is packaged and shipped in a container from which the synergist can be manually dispensed, such as a sachet as shown in FIG. 4, a squeeze bottle as shown in FIG. 5, or in any of a number of other convenient packaging containers that will be familiar to persons having ordinary skill in the art.

Sufficient synergist should be employed to provide the desired degree of colorant dispersion into the solvent-borne base paint or stain to be tinted, while leaving sufficient remaining headspace in the base paint or stain container to permit addition of the desired colorant amount Expressed on a volumetric basis, exemplary synergist amounts may for example be at least about 2, at least about 4, at least about 6, at least about 8 or at least about 10 mL of synergist per liter of solvent-borne base paint or stain to be tinted, and up to about 60, up to about 50, up to about 40, up to about 30 or up to about 20 mL of synergist per liter of solvent-borne base paint or stain to be tinted. If made containing a combination of ingredients, the synergist preferably provides a stable, homogeneous, non-settling composition that can be mixed into the base paint or stain in such exemplary amounts using a conventional paint stirrer or shaker and without forming visible clumps after mixing.

A variety of manual or automated colorant dispensers may be used in the disclosed system and method, including the HERO powdered colorant dispenser from BASF.

The disclosed custom-colored architectural paints and stains may be applied to a variety of substrates, e.g., asphalt (including asphalt composition shingles and membranes), cement, cement fiberboard and roofing tiles, ceramics, concrete, fabric, glass, metal, paper, plastic and wood (including monolithic, engineered and veneered wood), and other substrates that will be apparent to persons having ordinary skill in the art.

The invention is further described in the following Examples, in which all parts and percentages are by weight unless otherwise indicated.

EXAMPLES Example 1

The synergist formulation shown below in Table II was neutralized with potassium hydroxide to lessen its acidity and the potential for corrosion or off-gassing in metal containers. A liquid, non-associative thickener was included in the formulation to impart thixotropy and reduce the potential for separation, dripping or other storage stability or dispensing performance issues.

TABLE II Ingredient % Dioctyl Maleate Cosolvent 29.74 RHODOLINE ASP-100 Thickener 2.20 RHODACAL 330 Surfactant 66.08 Potassium hydroxide 1.98 Total 100%

Example 2

XFAST water-only powdered colorants from BASF were added without and with the synergist described in Table II to an alkyd base paint (Ace Royal polyurethane alkyd enamel No. 245A320 from Ace Hardware Corporation) and an oil-based stain (Cabot Semi-Transparent deck and siding stain No. 0306 from Valspar Corporation). For the tinted alkyd paint and stain, tint strength and rub-up were used to evaluate whether adding the synergist during colorant mixing provided improved compatibility. The tint strength test was performed as described above, and the rub-up test was performed as follows:

Rub-Up Test

The base paint or stain to be tested is placed in a tared jar equipped with a lidded closure, closed and weighed. The inside of the lid is coated by turning the jar over and back. The jar is opened and desired amounts of the colorant and optional synergist are added based on the weight per gallon of the tinted base (viz., the base after being combined with the colorant and optional synergist). The jar is closed and shaken on a FLACKTEK SPEEDMIXER™ for 1 or 10 minutes at 1800 rpm. Using a 4 mil BIRD™ film applicator for pastel, tint and midtone bases, and a 6 mil BIRD film applicator for ultradeep or clear bases, drawdown coating films are prepared and allowed to sit until the coating begins to dry around the edges, normally about 3-5 minutes for latex coatings and most alkyd coatings.

An index finger and mild pressure are employed to make even circular “rub-up” patterns on the upper outside edge of each coated film, applying shear to the coated areas without rubbing through the film, and normally using at least 5 and up to 25 rubs on each coated film. The films are allowed to air dry for 10 minutes and then forced dried in a 49° C. (120° F.) oven for at least 20 minutes. The dried films are compared visually and using a colorimeter to evaluate the extent of rub-up. The visual evaluation can be reported on a pass or fail basis based on the sample shaking time, and the rub-up characteristics can be reported as none, trace light, slight light, moderate light, severe light, trace dark, slight dark, moderate dark, or severe dark rub. The colorimeter evaluation can be reported as the strength difference ΔE based on measurements of ΔCRG, ΔCYB and ΔL.

The results for Example 2 are shown below in Table III and Table IV.

TABLE III Tinting alkyd base paint using water- only powdered colorants and synergist 3.24 weight percent water-only powdered colorant per gallon (3.8 L) of tinted base Tint Strength vs. No Powdered Colorant Synergist Amount Synergist Rub-up XFAST 8730 Green No Synergist — Severe dark XFAST 8730 Green 2.5 oz/gal synergist 212.93% Severe dark XFAST 8730 Green 10 oz/gal synergist 600.34% Severe dark XFAST 1256 Yellow No Synergist — Severe dark XFAST 1256 Yellow 2.5 oz/gal synergist 729.49% Severe dark XFAST 1256 Yellow 10 oz/gal synergist 567.10% Severe dark

TABLE IV Tinting oil-based stain using water- only powdered colorants and synergist 13.75 weight percent water-only powdered colorant per gallon (3.8 L) of tinted base Tint Strength vs. No Powdered Colorant Synergist Amount Synergist Rub-up XFAST 8730 Green No Synergist — Severe dark XFAST 8730 Green 2.5 oz/gal synergist 122.62% Severe dark XFAST 8730 Green 10 oz/gal synergist 230.63% Moderate dark XFAST 1256 No Synergist — Severe dark Yellow XFAST 1256 2.5 oz/gal synergist 158.18% Severe dark Yellow XFAST 1256 10 oz/gal synergist 117.82% Severe dark Yellow

The results in Table II and Table III show that when the synergist was not employed the colorants exhibited objectionable incompatibility when dispensed into either the alkyd base paint or the oil-based stain. Addition of the synergist improved the compatibility noted by increase in tint strength and color development as well as lessened the susceptibility to rub-up of the No. 8730 Green. Further optimization of the synergist formula should provide improved tint strength and reduced rub-up in the base paint or stain. Examples of such further optimization are shown below.

Example 3

Using the method of example 2, the synergist formulation was modified by inclusion of various commercially available materials, such as dispersants, surfactants, compatibilizers, solvents, and humectants. XFAST water-only powdered colorant No. 1256 Yellow from BASF was tested without and with a 5 fluid ounce per gallon addition of the synergist to an alkyd base paint (Ace Royal polyurethane alkyd enamel No. 245A320 from Ace Hardware Corporation). The results are shown below in Table IV:

TABLE IV Tinting alkyd base paint using water- only powdered colorants and synergist 3.24 weight percent water-only powdered colorant per gallon (3.8 L) of tinted base Tint Strength vs. No Synergist Synergist Rub-Up No Synergist — Severe dark 75:25 EG:DEG blend 6558.80% Slight dark AEROSOL OT-100 91.55% Severe dark BYK 9076 112.24% Severe dark BYK LPN 23366 129.19% Severe dark BYK-P 104 83.83% Severe dark DISPERBYK 110 192.71% Severe dark DISPERBYK 145 117.38% Severe dark DISPERBYK 167 96.14% Severe dark DISPERBYK 190 548.24% Severe dark DISPERBYK 2015 669.16% Severe dark DISPERBYK 2061 128.88% Severe dark DISPERBYK 2155 115.59% Severe dark DISPEX AA 4144 125.70% Severe dark DISPEX Ultra FA 4425 220.23% Severe dark GEROPON 99 218.33% Severe dark 3.24 weight percent water-only powdered colorant per gallon (3.8 L) of tinted base Synergist Tint Strength vs. No Rub-Up GEROPON SDS 109.55% Severe dark HOSTAPHAT 1306 177.68% Severe dark Lecithin Soya Yelkin 117.42% Severe dark PEG 300 1383.70% Severe dark PEG 400 1141.30% Severe dark Propylene Glycol 5154.40% Moderate dark RHODACAL VS1 303.88% Severe dark RHODAFAC RS-610 142.59% Severe dark RHODAFAC RS-710 266.57% Severe dark SOLSPERSE 53095 186.21% Severe dark SOLSPERSE 67000 138.06% Severe dark SOLSPERSE M387 174.84% Severe dark SOPROPHOR VS2 123.08% Severe dark TAMOL 731A 233.25% Severe dark TEGO DISPERS 1010 107.06% Severe dark Water 5565.60% Moderate dark

The results in Table IV show improvement in tint strength or susceptibility to rub up when adding water-only powdered colorants to alkyd base paints.

Example 4

A synergist formulation containing only cosolvents was prepared using the ingredients shown below in Table V:

TABLE V Ingredient % Ethylene glycol 75 Diethylene glycol 25 100%

Example 5

Using the method of Example 2, XFAST water-only powdered colorant No. 1256 Yellow from BASF was added without and with the synergist described in Table V to an alkyd base paint (Ace Royal polyurethane alkyd enamel No. 245A320 from Ace Hardware Corporation). The results are shown below in Table VI:

TABLE VI Tinting alkyd base paint using water- only powdered colorants and synergist 3.24 weight percent water-only powdered colorant per gallon (3.8 L) of tinted base Tint Strength vs. No Powdered Colorant Synergist Amount Synergist Rub-up XFAST 1256 No synergist — Severe dark Yellow XFAST 1256 1 oz/gal synergist 1866.30% Moderate dark Yellow XFAST 1256 3 oz/gal synergist 6621.30% Slight dark Yellow XFAST 1256 5 oz/gal synergist 6939.90% Slight dark Yellow XFAST 1256 7 oz/gal synergist 9856.70% Trace dark Yellow XFAST 1256 10 oz/gal synergist 20507.00% Trace dark Yellow

The results in Table VI show that when the synergist was not employed, No. 1256 Yellow exhibited objectionable incompatibility when dispensed into the alkyd base paint. The addition of the synergist significantly increased the color development as shown by the increase in tint strength, and significantly lessened the susceptibility to rub-up of the water-only powdered colorant with the alkyd base paint.

The invention is further illustrated by the following embodiments:

1. A point-of-sale custom color system for tinting base paints and stains, the system comprising:

-   -   a) an array of powdered colorants including at least white,         green, blue and red colorants, the colorants being packaged in         containers from which colorant may be gravimetrically or         volumetrically dispensed via an automated or manual colorant         dispenser into the base paint or stain; and     -   b) at least one synergist containing, primarily or exclusively,         one or more ingredients that will disperse the powdered         colorants into solvent-borne base paints or stains.

2. A system according to embodiment 1, further comprising at least one water-borne base paint or stain and at least one solvent-borne base paint or stain, the base paints or stains being packaged in largely but incompletely filled point-of-sale containers with a volume of 0.2 to 20 L equipped with an openable and recloseable lid, cap or other closure for an opening through which colorant may be dispensed from the automated or manual colorant dispenser into the base paint or stain.

3. A system according to embodiment 1, further comprising the automated or manual colorant dispenser.

4. A point-of-sale custom color system for tinting base paints and stains, the system comprising:

-   -   a) an array of powdered colorants including at least white,         green, blue and red colorants, the colorants being packaged in         containers from which colorant may be gravimetrically or         volumetrically dispensed via an automated or manual colorant         dispenser into the base paint or stain; and     -   b) at least one water-borne base paint or stain and at least one         solvent-borne base paint or stain, the base paints or stains         being packaged in largely but incompletely filled point-of-sale         containers with a volume of 0.2 to 20 L equipped with an         openable and recloseable lid, cap or other closure for an         opening through which colorant may be dispensed from the         automated or manual colorant dispenser into the base paint or         stain, wherein the solvent-borne base paint or stain includes a         synergist in the form of one or more ingredients that will         disperse the powdered colorants into such solvent-borne base         paint or stain.

5. A system according to embodiment 4, further comprising the automated or manual colorant dispenser.

6. A method for point-of-sale custom paint or stain tinting, the method comprising using an automated or manual colorant dispenser to dispense into water-borne and solvent-borne base paints or stains at a retail, wholesale or combined retail/wholesale outlet one or more powdered colorants selected from an array of colorants including at least white, black, red, green and blue powdered colorants, and further comprising adding to or including in the solvent-borne base paints or stains at least one synergist containing one or more ingredients that will disperse the powdered colorants into such solvent-borne base paints or stains.

7. A method according to embodiment 6, wherein the synergist is added to the solvent-borne base paint or stain before dispensing any of the one or more powdered colorants into such solvent-borne base paint or stain.

8. A system according to embodiment 4 or method according to embodiment 6, wherein the solvent-borne base paints or stains do not already include sufficient ingredients from the synergist to disperse the powdered colorants into such solvent-borne base paint or stains without causing objectionable rub-up.

9. A system according to embodiment 4 or method according to embodiment 6, wherein the synergist is included in the solvent-borne base paint or stain.

10. A system or method according to any preceding embodiment, wherein the synergist is disposed in one or more tinting machine dispenser slots normally reserved for a colorant, and dispensed into the base paint or stain using a tinting machine metering circuit.

11. A system or method according to any preceding embodiment, wherein powdered colorants are used whenever tinting a water-borne base paint or stain, and powdered colorants and the synergist are used whenever tinting a solvent-borne base paint or stain.

12. A system or method according to any preceding embodiment, wherein the array includes one or more yellow and one or more colored oxide colorants.

13. A system or method according to any preceding embodiment, wherein the synergist comprises a surfactant, optional dispersing agent and optional cosolvent.

14. A system or method according to any preceding embodiment, wherein the synergist comprises a combination of two or more surfactants that provides improved compatibility across a range of base paints or stains or within an array of water-only colorants.

15. A system or method according to any preceding embodiment, wherein the synergist comprises a nonionic surfactant.

16. A system or method according to any preceding embodiment, wherein the synergist comprises one or more cosolvents.

17. A system or method according to embodiment 16, wherein the synergist has a molecular weight less than 200 g/mol.

18. A system or method according to any preceding embodiment, wherein the synergist comprises a mixture of ethylene glycol and diethylene glycol.

19. A system or method according to any preceding embodiment, wherein the synergist comprises a dispersing agent.

20. A system or method according to any preceding embodiment, wherein the synergist comprises a compound having the formula I shown below: R₁O(C(O))_(m)A(R₃)(R₄)(C(O))_(n)R₂  I

-   -   wherein: A is a divalent C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl or C₃-C₁₀         cycloalkyl radical;     -   R₃ and R₄ are independently H, substituted or unsubstituted         C₁-C₆ alkyl, substituted or unsubstituted C₃-C₆ cycloalkyl, —OR₅         or C(O)OR₅ radicals, wherein R₅ is H or a substituted or         unsubstituted C₁-C₆ alkyl, substituted or unsubstituted C₃-C₆         cycloalkyl, or C₁-C₆ alkoxy radical;     -   R₁ and R₂ are independently H, —C═O, or a substituted or         unsubstituted C₁-C₆ alkyl radical;     -   m is 0 or 1; and     -   n is 0 or 1.

21. A system or method according to any preceding embodiment, wherein the synergist comprises a surfactant.

22. A system or method according to any preceding embodiment, wherein the synergist is contained in a metal or plastic box, can, cartridge, jar, pouch, squeeze bottle, syringe or collapsible tube.

23. A system or method according to any preceding embodiment, wherein the amount and type of synergist added to the solvent-borne base paint or stain is the same whenever a solvent-borne base paint or stain is tinted.

24. A system or method according to any preceding embodiment, wherein the amount or type of synergist added to the solvent-borne base paint or stain varies depending on the amount of colorant to be dispensed.

25. A system or method according to any preceding embodiment, wherein the amount or type of synergist added to the solvent-borne base paint or stain varies depending on the colorant to be dispensed.

26. A system or method according to any preceding embodiment, wherein the amount or type of synergist added to the solvent-borne base paint or stain varies depending on the solvent-borne base paint or stain to be tinted.

27. A system or method according to any preceding embodiment, wherein all of the colorants in the array and in the colorant dispenser are water-only powdered colorants.

28. A system or method according to any preceding embodiment, wherein less than two of the colorants in the array and in the colorant dispenser are compatible with alkyd paints and stains, and the remaining colorants in the array will exhibit insufficient tint strength or visually objectionable rub-up if dispensed into such alkyd paints and stains in representative tinting amounts of 1 to 15% of the alkyd paint or stain weight.

29. A system or method according to any preceding embodiment, wherein the solvent-borne base paint or stain is a paint.

30. A system or method according to any preceding embodiment, wherein the solvent-borne base paint or stain comprises an alkyd paint.

31. A system or method according to any preceding embodiment, wherein the solvent-borne base paint or stain comprises a polyurethane paint.

32. A system or method according to any preceding embodiment, wherein the solvent-borne base paint or stain comprises an epoxy paint.

33. A system or method according to any preceding embodiment, wherein the solvent-borne base paint or stain is an oil-based stain.

Having thus described the preferred embodiments of the present invention, those of skill in the art will readily appreciate that the teachings found herein may be applied to yet other embodiments within the scope of the claims hereto attached. The complete disclosure of all patents, patent documents, and publications are incorporated herein by reference as if individually incorporated. 

The invention claimed is:
 1. A method for point-of-sale custom paint or stain tinting, the method comprising using an automated or manual colorant dispenser to dispense into water-borne and solvent-borne base paints or stains at a retail, wholesale or combined retail/wholesale outlet one or more powdered colorants selected from an array of colorants including at least white, black, red, green and blue powdered colorants containing pigment or dye and a surface treatment, and further comprising adding to or including in the solvent-borne base paints or stains at least one synergist containing one or more ingredients that will disperse the powdered colorants into such solvent-borne base paints or stains, wherein the synergist is added to the solvent-borne base paint or stain before dispensing any of the one or more powdered colorants into such solvent-borne base paint or stain.
 2. A method according to claim 1, wherein powdered colorants are used whenever tinting a water-borne base paint or stain, and powdered colorants and the synergist are used whenever tinting a solvent-borne base paint or stain.
 3. A method according to claim 1, wherein the amount or type of synergist added to the solvent-borne base paint or stain varies depending on the amount or type of colorant to be dispensed, or depending on the solvent-borne base paint or stain to be tinted.
 4. A method according to claim 1, wherein the synergist comprises an anionic surfactant.
 5. A method according to claim 1, wherein the synergist comprises surfactant and cosolvent.
 6. A method according to claim 1, wherein the synergist comprises surfactant, cosolvent and rheology modifier.
 7. A method according to claim 1, wherein the synergist comprises surfactant and dispersing agent.
 8. A method according to claim 1, wherein at least 80 wt. % of the synergist comprises surfactant or dispersing agent or cosolvent.
 9. A method according to claim 1, wherein the synergist comprises surfactant, cosolvent and rheology modifier.
 10. A method according to claim 1, wherein the synergist further comprises an adhesion promoter.
 11. A method according to claim 1, wherein the synergist further comprises a diluent.
 12. A method according to claim 11, wherein the diluent is a reactive diluent.
 13. A method according to claim 1, wherein the synergist is contained in a metal or plastic box, can, cartridge, jar, pouch, squeeze bottle, syringe or collapsible tube.
 14. A method according to claim 1, wherein all of the colorants in the array are water-only powdered colorants.
 15. A method according to claim 1, wherein the solvent-borne base paint or stain comprises an alkyd paint, polyurethane paint, epoxy paint or oil-based stain.
 16. A method for point-of-sale custom paint or stain tinting, the method comprising using an automated or manual colorant dispenser to dispense into water-borne and solvent-borne base paints or stains at a retail, wholesale or combined retail/wholesale outlet one or more powdered colorants selected from an array of colorants including at least white, black, red, green and blue powdered colorants containing pigment or dye and a surface treatment, and further comprising adding to or including in the solvent-borne base paints or stains at least one synergist containing one or more ingredients that will disperse the powdered colorants into such solvent-borne base paints or stains, wherein powdered colorants are used whenever tinting a water-borne base paint or stain, and powdered colorants and the synergist are used whenever tinting a solvent-borne base paint or stain.
 17. A method according to claim 16, wherein the synergist is added to the solvent-borne base paint or stain before dispensing any of the one or more powdered colorants into such solvent-borne base paint or stain.
 18. A method according to claim 16, wherein the amount or type of synergist added to the solvent-borne base paint or stain varies depending on the amount or type of colorant to be dispensed, or depending on the solvent-borne base paint or stain to be tinted.
 19. A method according to claim 16, wherein the synergist comprises an anionic surfactant.
 20. A method according to claim 16, wherein the synergist comprises surfactant and cosolvent.
 21. A method according to claim 16, wherein the synergist comprises surfactant, cosolvent and rheology modifier.
 22. A method according to claim 16, wherein the synergist comprises surfactant and dispersing agent.
 23. A method according to claim 16, wherein at least 80 wt. % of the synergist comprises surfactant or dispersing agent or cosolvent.
 24. A method according to claim 16, wherein the synergist comprises surfactant, cosolvent and rheology modifier.
 25. A method according to claim 16, wherein the synergist further comprises an adhesion promoter.
 26. A method according to claim 16, wherein the synergist further comprises a diluent.
 27. A method according to claim 26, wherein the diluent is a reactive diluent.
 28. A method according to claim 16, wherein the synergist is contained in a metal or plastic box, can, cartridge, jar, pouch, squeeze bottle, syringe or collapsible tube.
 29. A method according to claim 16, wherein all of the colorants in the array are water-only powdered colorants.
 30. A method according to claim 16, wherein the solvent-borne base paint or stain comprises an alkyd paint, polyurethane paint, epoxy paint or oil-based stain. 